Effects Of Site And Magnetic Disorder On The Oxygen Vacancy Formation And Electronic And Optical Properties Of Laxsr1-Xcoo3-Delta And Srfeyco1-Yo3-Delta

Disorder is an inevitable issue in practical applications of perovskites with the A-site occupied by La/Sr and the B-site occupied by Co/Fe. We performed density functional theory calculations to reveal the site and magnetic disorder effect on the oxygen vacancy formation and the electronic and optical properties of LaxSr1-xCoO3-delta and SrFeyCo1-yO3-delta systems. Generally, site disorder has little influence on the physical properties we studied, while magnetic disorder has a property-dependent effect for La A-site and Fe B-site doping of SrCoO3. Compared to ordered ferromagnetic (FM) calculations, disordered paramagnetic (PM) results can better describe the high-temperature behavior of lattice expansion and the multiple spin states of Co ions in LaxSr1-xCoO3. The oxygen vacancy formation energy results show that the magnetic disorder has a more remarkable effect on SrFeyCo1-yO3-delta systems with a robust magnetic order than that on the LaxSr1-xCoO3-delta systems with a fragile magnetic order. The electronic structures in the PM phase have less spin polarization and broadened bands, by which the optical absorptions from the single spin channel transition in the FM phase have an obvious change in the magnitude and/or the trend. Our work provides guidance for where and why to consider the disorder.